Developers (two dudes) are super responsive and would likely release an IP customization feature upon request. Is there any service that would tolerate this [D]DOS-y kind of behavior that would feel more privacy friendly than Cloudflare?
IsThereNet [for macOS] watches for internet connection status changes and draws a colored line at the top of the screen to indicate the status.
Maybe a pool of big corp captive portal / connectivity test servers? For example:
https://developers.cloudflare.com/cloudflare-one/connections/connect-devices/warp/deployment/firewall/#captive-portal
https://android.googlesource.com/platform/frameworks/base/+/refs/tags/android-9.0.0_r49/services/core/java/com/android/server/connectivity/NetworkMonitor.java#101
Clever! Thanks for finding those links too.